Typically a yoke forming an electromagnetic apparatus, the upper and lower edges located at the coil winding part of yoke are cut out and a coil is wound around this coil winding part in order to form a thin electromagnetic apparatus. However, there is a disadvantage to such a yoke of the prior art, in that reduction of sectional area generated by cutting out part of the coil winding part increases magnetic resistance and thereby lowers the attractive force and sensitivity of the electromagnetic apparatus.
To overcome these, as illustrated in FIG. 5 and FIG. 6, has been used wherein pair of yoke segment 2, 5 are formed by extending the almost L-shaped wide iron segment attracting portions 4, 7 from the one end of the coil winding parts 3, 6 and bending such iron segment attracting portions 4, 7 in almost right angles from the boundaries 3a, 6a. The coil winding portion 3 of yoke segment 2 is longitudinally disposed on coil winding part 6 of the other yoke segment 5 and simultaneously the end surface of coil winding part 3 is placed in contact with the internal side of the wide iron segment attracting portion 7.
However, such a yoke provides a problem in that; since the end part of coil winding part 6 is not in contact with the iron segment attracting part 4 of the other yoke segment 2, the sectional area of boundary 3a of yoke segment 2 is locally reduced and the attractive force and sensitivity are lowered because of the increase of magnetic resistance.